1. Field of the Invention
The invention relates to an image sensor which can be used for a facsimile, a copying apparatus, a scanner, and the like and which reads reflection light from a read original surface by a sensor.
2. Related Background Art
Hitherto, as an original reading apparatus which is used for a facsimile, a copying apparatus, a scanner, or the like, there is a contact type image sensor for forming read images in a one-to-one corresponding manner by using a sensor array and reading the images at the same size as that of the read original.
In an example shown in FIG. 11, the contact type image sensor is constructed such that a sensor board 118 on which a plurality of sensor chips 112 on each of which a plurality of pixels for performing a photoelectric conversion are arranged and a protecting film 114 for protecting the plurality of sensor chips 112 are mounted, a light source 117 for irradiating light onto an original to be read, a rod lens array 102 serving as a lens for forming an image of the read original to the pixels of the sensor chips 112, and a cover glass 101 serving as an original reading surface are attached to a frame 109 serving as supporting means.
In the contact type image sensor, input/output terminals 124 of the sensor board 118 on which the plurality of sensor chips 112 are mounted and electric circuit wirings to drive the sensor chips are arranged and driving terminals of the light source for irradiating the original are formed by different constructions at remote positions. According to the sensor board 118, a wiring pattern is formed by a conductor such as Ag-Pd or the like onto a ceramics board and the surface on the wiring pattern is protected by an insulating coating material. The input/output terminals 124 of the circuit wirings are conductive terminals which are arranged at an equal pitch on the side of the sensor chip installing surface and have an area which enables the electrical connection to the outside, connecting parts, or the like.
The light source 117 uses an LED array in which a plurality of LED devices or the like are arranged in order to irradiate the light to a region of a length corresponding to the original reading size. Lead wires 123 or the like are used as driving terminals of the LED array. FIG. 12 is a detailed diagram of this portion. According to those two terminal portions, first, a flexible printed circuit board 116 (hereinafter, abbreviated as an FPC) is connected to the terminal portion 124 of the sensor board 118, the FPC 116 connected to the sensor array 119 and the lead wires 123 of the LED array are soldered to a printed circuit board 126 (glass epoxy or the like) on which sensor chip driving parts, connectors, and the like are mounted, inputs and outputs to/from the outside are enabled to be performed in a lump by one connector 115 or the like, and after that, the printed circuit board 126 is fixed to the frame 109, thereby constructing a contact type image sensor as shown in FIG. 13.
In the example shown in FIG. 14, a sensor board 218 is a printed circuit board (refer to FIGS. 15 and 16) made of a glass epoxy resin or the like in which wirings are formed on both surfaces. Not only circuit wirings for driving the sensor chips but also terminals 225 for connecting a light source are formed in edge portions of the back surface of the board 218. Wirings from the terminals 225 are also conductor terminals in which concentrated inputting/outputting terminals 224 are arranged at an equal pitch on the back surface on the side opposite to the sensor chip installing surface and each of which has an area that enables an electrical connection to the outside or connecting parts or the like. As a light source 217, a structure in which an LED package comprising one or more LED devices or the like is arranged at the edge surface on a light guiding plate 205 for guiding the light in the main scanning direction and converging it to an original reading portion is used. Driving terminals of the light source serve as a lead frame 204. In this case, as shown in FIG. 16, as for each terminal, terminals 223 of the lead frame 204 of the light source are soldered to the light source connecting terminals 225 provided in the edge portion of the back surface of the sensor board 218 and a connecting part such as a connector 215 or the like which can perform inputs and outputs to/from the outside in a lump by one part is attached to the terminals 224 for inputting and outputting, thereby constructing a contact type image sensor as shown in FIG. 17.
In the foregoing contact type image sensor, however, in order to construct in a manner such that the input/output terminals 124 of the sensor board 118 and the driving terminals of the light source 117 which are formed by the different constructions at the remote positions are concentrated to the connecting medium such as a connector 115 or the like and the inputs and outputs can be executed in a lump, relay connecting media such as FPC 116, individual printed circuit board 126, and the like are needed. Consequently, since the component parts are complicated and enlarged in size, assembling performance deteriorates. The costs rise due to an increase in the number of parts or the like.
It is an object of the invention to provide a small image sensor which can be easily assembled.
To accomplish the above object, according to a preferred embodiment of the invention, there is provided an image sensor comprising: a light source for irradiating an original; a sensor board on which a plurality of sensor chips are mounted; and a single connecting medium which is directly connected to lead terminals of the light source and input/output terminals of the sensor board and is used to perform inputs and outputs to/from an outside in a lump.
With this construction, a small image sensor which can be easily assembled can be provided.
The above and other objects and features of the present invention will become apparent from the following detailed description and the appended claims with reference to the accompanying drawings.